Methods and systems for rapid detection of concealed objects

Abstract

This specification is directed towards finding, locating, and confirming threat items and substances. The inspection system is designed to detect objects that are made from, but not limited to, special nuclear materials (“SNM”) and/or high atomic number materials. The system employs a dual energy CT scanning first stage inspection system and advanced image processing techniques to analyze images of an object under inspection (“OUI”), which includes, but is not limited to baggage, parcels, vehicles and cargo.

I claim: 
     
       1. An apparatus for inspecting an object, comprising:
 a first stage inspection system comprising a conveyor for transporting the object into a first inspection volume, a dual energy X-ray source wherein said dual energy X-ray source is configured to irradiate said first inspection volume with dual energy radiation, and a detector array positioned opposite said dual energy X-ray source, configured to receive dual energy radiation transmitted through said object, and adapted to generate signals, comprising high energy data component and low energy data, based upon said received dual energy radiation; and 
 at least one processor for processing said signals to generate a three dimensional image of said object and to locate a threat within said object and for plotting said high energy data against said low energy data to identify at least one of spectra, parameters of analytical expressions, or spectral attenuation functions in a lookup table. 
 
     
     
       2. The apparatus of  claim 1  wherein said first stage inspection system is adapted to identify a location of the threat within said object and to communicate said location to a human operator. 
     
     
       3. The apparatus of  claim 1  wherein said first stage inspection system is adapted to identify a location of the threat within said object and to communicate said location to a second stage inspection system. 
     
     
       4. The apparatus of  claim 3  wherein the second stage inspection system inspects said location to confirm the existence of said threat. 
     
     
       5. The apparatus of  claim 3  wherein the second stage inspection system produces a second set of data having an X-ray signature characteristic of a material in said location. 
     
     
       6. The apparatus of  claim 5  wherein the X-ray signature characteristic is at least one of mass, degree of attenuation, area, atomic number, size, shape, pattern, or context. 
     
     
       7. The apparatus of  claim 3  wherein the second stage inspection system determines the existence of said threat by subjecting said object to radiation and detecting at least one of diffracted radiation or scattered radiation. 
     
     
       8. The apparatus of  claim 7  wherein the second stage inspection system comprises a detector array having transmission detectors and energy-dispersive detectors. 
     
     
       9. The apparatus of  claim 1  wherein said first stage inspection system is adapted to pass said object to a bypass conveyor when said processor determines that said object does not contain a threat. 
     
     
       10. The apparatus of  claim 1  wherein said three dimensional image is generated by rotating said dual energy X-ray source and said detector array around said object. 
     
     
       11. The apparatus of  claim 1  wherein said processor determines a location by analyzing the three dimensional image and determining a set of coordinates for the location based upon said three dimensional image. 
     
     
       12. The apparatus of  claim 11  wherein said analysis comprises computing densities for a plurality of voxels within said three dimensional image. 
     
     
       13. The apparatus of  claim 1  wherein said detector array comprises at least one first detector and at least one second detector, wherein said first detector is positioned in front of the second detector relative to a pathway of said transmitted dual energy radiation. 
     
     
       14. The apparatus of  claim 13  wherein said first detector is configured to detect more lower energy photons than said second detector. 
     
     
       15. The apparatus of  claim 14  wherein said second detector is configured to detect more higher energy photons than said first detector. 
     
     
       16. The apparatus of  claim 1  wherein the processor processes said signals to discriminate between pairs of similar materials, wherein said pairs of similar materials comprises at least one pair selected from a) a plastic comprised of more oxygen and nitrogen atoms than hydrogen and carbon atoms and a plastic comprised of more hydrogen and carbon atoms than oxygen and nitrogen atoms and b) a material having more aluminum than steel and a material having more steel than aluminum. 
     
     
       17. An apparatus for inspecting an object, comprising:
 a first stage inspection system comprising a conveyor for transporting the object into a first inspection volume, a dual energy X-ray source wherein said dual energy X-ray source is configured to irradiate said first inspection volume with dual energy radiation, and a detector array positioned opposite said dual energy X-ray source, configured to receive dual energy radiation transmitted through said object, and adapted to generate signals, comprising high energy data component and low energy data, based upon said received dual energy radiation; 
 at least one processor for processing said signals to generate a three dimensional image of said object, to locate a threat within said object, to generate a signal comprising data defining said location and to map said high energy data against said low energy data to identify at least one of spectra, parameters of analytical expressions, or spectral attenuation functions in a lookup table; and 
 a second stage inspection system comprising a radiation source and a detector array having at least one transmission detector or energy-dispersive detector, wherein said second stage inspection system inspects said object based on said location. 
 
     
     
       18. The apparatus of  claim 17  wherein the second stage inspection system produces a second set of data having an X-ray signature characteristic of a material in said location, wherein the X-ray signature characteristic is at least one of mass, degree of attenuation, area, atomic number, size, shape, pattern, or context. 
     
     
       19. The apparatus of  claim 17  wherein said detector array of the first stage inspection system comprises at least one first detector and at least one second detector, wherein said first detector is configured to detect more lower energy photons than said second detector, and wherein said second detector is configured to detect more higher energy photons than said first detector. 
     
     
       20. The apparatus of  claim 19  wherein the processor processes said signals to discriminate between pairs of similar materials, wherein said pairs of similar materials comprises at least one pair selected from a) a plastic comprised of more oxygen and nitrogen atoms than hydrogen and carbon atoms and a plastic comprised of more hydrogen and carbon atoms than oxygen and nitrogen atoms and b) a material having more aluminum than steel and a material having more steel than aluminum.